The disclosure relates to a wireless power transmitter and a method of transmitting power thereof.
A wireless power transmission or a wireless energy transfer refers to a technology of wirelessly transferring electric energy to desired devices. In the 1800's, an electric motor or a transformer employing the principle of electromagnetic induction has been extensively used and then a method of transmitting electrical energy by irradiating electromagnetic waves, such as radio waves or lasers, has been suggested. Actually, electrical toothbrushes or electrical razors, which are frequently used in daily life, are charged based on the principle of electromagnetic induction. Until now, the long-distance transmission using the magnetic induction, the resonance and the short-wavelength radio frequency has been used as the wireless energy transfer scheme.
Recently, among the wireless power transmission technologies, an energy transfer scheme using resonance has been extensively used.
Since a wireless power transmission system based on resonance transmits electrical signals formed at transmitter and receiver sides through a coil in wireless, a user can easily charge an electronic device such as a portable device with electricity.
However, according to a current wireless charging technology, only a single portable receiver is charged by using a single source, and the distance between power transmission and reception sides is very restricted.
Particularly, in order to wirelessly charge multiple appliances with power, the area of the resonant coil may be increased (Korean Unexamined Patent Publication No. 10-2010-0026075). In this case, an undesirable magnetic field is generated even in a region without the wireless power receiver, so that the very low power transmission efficiency is represented, and the intensity of harmful electromagnetic field leaking to the outside is increased, so that problems may be occur in terms of the harmfulness to the human body.